In modern society, people are using devices (e.g., mobile electronic devices) increasingly more in their everyday lives. For instance, people often carry devices with which they can discover information (e.g., using a digital personal assistant), perform work, consume audio and/or video content, and communicate with friends, coworkers, and family members. A conventional device typically has a relatively small speaker that is unable to create high-volume, low-frequency sounds. For instance, the speaker may include a vibrating membrane that is too small to generate low-frequency sounds.
A variety of techniques has been proposed for improving low-frequency response of devices. However, each such technique has its limitations. In one example, a resonance cavity (a.k.a. boom box) is incorporated into a device to amplify low frequencies. However, a trend in the marketplace is for device manufacturers to produce increasingly thinner devices, which may limit the size of resonance cavities incorporated therein. Such a size-constrained resonance cavity may not be able to adequately amplify the low frequencies.
In another example, a device may be placed in a container (e.g., a cup), or a tube (e.g., a toilet paper roll) may be attached to the device, to amplify sounds that are generated by the device. However, such a container or tube traditionally is not acoustically calibrated and therefore typically causes the generation of standing waves. Such standing waves often reduce clarity of the sounds that are generated by the device. For instance, harmonics of lower frequencies may interfere with higher frequencies.
In yet another example, digital signal processing is used to “fake” a desired low frequency. For instance, if a frequency of 250 Hz is desired, 250 Hz may be faked by exciting frequencies that are slightly different from 250 Hz. For example, frequencies of 255 Hz, 260 Hz, and 275 Hz may be excited in addition to or in lieu of 250 Hz to increase an apparent loudness of a 250 Hz signal. However, faking a desired low frequency often results in a signal having reduced clarity. For instance, the signal may sound “muddy.”